How do I purchase a Barbie doll for my 3 year old daughter?

I heard that Barbie dolls are a good thing to buy three year old girls. But I can't figure out how to get money, or where I go to get them, or how I even can spend money. Can you help?
PS. The Canadian government has me under surveillance because I once tried to steal a human, and take them to my ship. I'm... show more I heard that Barbie dolls are a good thing to buy three year old girls. But I can't figure out how to get money, or where I go to get them, or how I even can spend money. Can you help?
PS. The Canadian government has me under surveillance because I once tried to steal a human, and take them to my ship. I'm worried I'm going to get in trouble again.